Exceptions, errors thrown on manifest reload in latest dev reference player

Created by: davemevans

Environment

• The MPD passes the DASH-IF Conformance Tool on http://dashif.org/conformance.html
• The stream has correct Access-Control-Allow-Origin headers (CORS)
• There are no network errors such as 404s in the browser console when trying to play the stream
• The issue observed is not mentioned on https://github.com/Dash-Industry-Forum/dash.js/wiki/FAQ
• The issue occurs in the latest reference client on http://reference.dashif.org/dash.js/ and not just on my page

• Link to playable MPD file: https://dash.akamaized.net/akamai/bbb_30fps/bbb_30fps.mpd
• Dash.js version: latest
• Browser name/version: Chrome 64
• OS name/version: Win7

Steps to reproduce

1. In reference client, click load on default stream and wait for it to start playing
2. Let it play for a few seconds, then click load again. Note devtools console.

Observed behaviour

The following errors occur:

TypeError: videoElement.setMediaKeys is not a function
    at Object.setMediaElement (ProtectionModel_21Jan2015.js:151)
    at Object.setMediaElement (ProtectionController.js:255)
    at Object.reset (StreamController.js:874)
    at resetAndInitializePlayback (MediaPlayer.js:2453)
    at Object.attachSource (MediaPlayer.js:2376)
    at m.$scope.doLoad (main.js:402)
    at fn (eval at compile (angular.min.js:233), <anonymous>:4:209)
    at b (angular.min.js:126)
    at e (angular.min.js:276)
    at m.$eval (angular.min.js:145)

and

MediaPlayer.js:626 Uncaught You must first call initialize() to init playback before calling this method

This behaviour appears to have been introduced recently - 2.6.6 does not have this problem.